ormlite-android-4.29, ormlite-core-4.29
I have a ForiegnCollection of PantryCheckLine objects like this in my PantryCheck class.
#ForeignCollectionField(eager = true, maxEagerForeignCollectionLevel = 1)
private ForeignCollection<PantryCheckLine> pantryCheckLines;
Let's say I had 3 PantryCheckLines objects and I deleted one. Then I want to delete the PantryCheck with combined PantryCheckLines of it. Everything seems working. But the size of the ForiegnCollectionis not correct.
deleting method as follows.
PantryCheckLineRepo pantryCheckLineRepo =
new PantryCheckLineRepo(DaoFactory.getPantryCheckLineDaoInstance());
Collection<PantryCheckLine> pantryCheckLinesCollection =
this.getPantryCheckLines();
Log.v("pantrychecklines size", pantryCheckLinesCollection.size());
pantryCheckLineRepo.delete(pantryCheckLinesCollection);
Log.v("pantrychecklines", "deleted");
appreciate your help.
I can't answer specifically because I'm not sure what the delete() method is doing. If you edit your question with more details about what Dao calls or ForeignCollection calls are being made, I can add details here.
The only way the collection size would be affected is if you used the remove(Object) method on the collection itself. If you used the Dao to delete the item behind the scenes then the collection would not know that the delete happened and its eager fetched internal list size would not be affected. The lazy collections (eager = false) always go to the database so either remove(Object) or dao.delete(Object) would work.
Hope this helps.
Related
I am using Tastypie, Django for my project.
To Update a many to many field I have used save_m2m hook.
def save_m2m(self, bundle):
for field_name, field_object in self.fields.items():
if not getattr(field_object, 'is_m2m', False):
continue
if not field_object.attribute:
continue
if field_object.readonly:
continue
related_mngr = getattr(bundle.obj, field_object.attribute)
related_objs = []
print bundle.data[field_name]
for related_bundle in bundle.data[field_name]:
try:
stock = Stock.objects.get(nse_symbol = related_bundle.obj.nse_symbol)
print stock.__dict__
except Stock.DoesNotExist as e:
dataa = {"error_message": e}
raise ImmediateHttpResponse(response=HttpBadRequest(content=json.dumps(dataa), content_type="application/json; charset=UTF-8"))
related_objs.append(stock)
related_mngr.add(*related_objs)
Now I want to remove elements from the same many to many field.
How should I achieve this. Do I have to send a patch request or delete request and how to handle this.
I am begineer in tastypie. I googled it some time and I couldn't find a proper way. Please guide me how to complete this.
Thanks.
I've thought a lot about handing m2m relationships, since most of our app depends on m2m links.
I've settled for the approach of an update method. Pass in the all the references of the relationships you want changed (add and remove), then update the db accordingly. We only pass in the changed values, since if you have a paginated list, you only want to update the items the user has identified. Generally I use a custom hook for this defined in override_urls.
I used to have a separate add and remove method, which worked well until we changed the gui and allowed users simply to change checkboxes. In that approach having an update method was much more useful. You'll have to decide on which method suits your application the best.
My question is this: How can you implement a default server-side "filter" for a navigation property?
In our application we seldom actually delete anything from the database. Instead, we implement "soft deletes" where each table has a Deleted bit column. If this column is true the record has been "deleted". If it is false, it has not.
This allows us to easily "undelete" records accidentally deleted by the client.
Our current ASP.NET Web API returns only "undeleted" records by default, unless a deleted argument is sent as true from the client. The idea is that the consumer of the service doesn't have to worry about specifying that they only want undeleted items.
Implementing this same functionality in Breeze is quite simple, at least for base entities. For example, here would be the implementation of the classic Todo's example, adding a "Deleted" bit field:
// Note: Will show only undeleted items by default unless you explicitly pass deleted = true.
[HttpGet]
public IQueryable<BreezeSampleTodoItem> Todos(bool deleted = false) {
return _contextProvider.Context.Todos.Where(td => td.Deleted == deleted);
}
On the client, all we need to do is...
var query = breeze.EntityQuery.from("Todos");
...to get all undeleted Todos, or...
var query = breeze.EntityQuery.from("Todos").withParameters({deleted: true})
...to get all deleted Todos.
But let's say that a BreezeSampleTodoItem has a child collection for the tools that are needed to complete that Todo. We'll call this "Tools". Tools also implements soft deletes. When we perform a query that uses expand to get a Todo with its Tools, it will return all Tools - "deleted" or not.
But how can I filter out these records by default when Todo.Tools is expanded?
It has occurred to me to have separate Web API methods for each item that may need expanded, for example:
[HttpGet]
public IQueryable<Todo> TodoAndTools(bool deletedTodos = false, bool deletedTools = false)
{
return // ...Code to get filtered Todos with filtered Tools
}
I found some example code of how to do this in another SO post, but it requires hand-coding each property of Todo. The code from the above-mentioned post also returns a List, not an IQueryable. Furthermore this requires methods to be added for every possible expansion which isn't cool.
Essentially what I'm looking for is some way to define a piece of code that gets called whenever Todos is queried, and another for whenever Tools is queried - preferably being able to pass an argument that defines if it should return Deleted items. This could be anywhere on the server-side stack - be it in the Web API method, itself, or maybe part of Entity Framework (note that filtering Include extensions is not supported in EF.)
Breeze cannot do exactly what you are asking for right now, although we have discussed the idea of allowing the filtering of "expands", but we really need more feedback as to whether the community would find this useful. Please add this to the breeze User Voice and vote for it. We take these suggestions very seriously.
Moreover, as you point out, EF does not support this.
But... what you can do is use a projection instead of an expand to do something very similar:
public IQueryable<Object> TodoAndTools(bool deleted = false
,bool deletedTools = false) {
var baseQuery = _contextProvider.Context.Todos.Where(td => td.Deleted == deleted);
return baseQuery.Select(t => new {
Todo: t,
Tools: t.Tools.Where( tool => tool.Deleted = deletedTools);
});
}
Several things to note here:
1) We are returning an IQueryable of Object instead of IQueryable of ToDo
2) Breeze will inspect the returned payload and automatically create breeze entities for any 'entityTypes' returned (even within a projection). So the result of this query will be an array of javascript objects each with two properties; 'ToDo' and 'Tools' where Tools is an array of 'Tool' entities. The nice thing is that both ToDo and Tool entities returned within the projection will be 'full' breeze entities.
3) You can still pass client side filters based on the projected property names. i.e.
var query = EntityQuery.from("TodoAndTools")
.where("Todo.Description", "startsWith", "A")
.using(em);
4) EF does support this.
I have the following in a config.ini file: (Zend_Form_Element)
site_status.name = "site_status"
site_status.type = "select"
site_status.label = "Status"
site_status.options.multiOptions.active.key = "Active"
site_status.options.multiOptions.active.value = "Active"
site_status.options.multiOptions.active.key = "Inactive"
site_status.options.multiOptions.active.value = "Inactive"
As you can see this is supposed to be a dropdown (select) box, however it is being rendered as a standard text box. What am I doing wrong?
--> Edit
Rather than tying the elements to a form, I am trying to tie them to a database: In my code it would look something like this:
[{tablename}] // the table name would represent a section in the ini
{column}.name = "{column_name/form_field_id}";
{column}.type = "{form_element_type}"
{column}.label = "{form_element_label}"
...
From there I would pull in the database table(s) that the form would represent data for (one or more tables as necessary). As far as the reasoning for this approach is that (down the road), I want to define (either by ini or some other storage method), a configuration file that would be a list of fields/elements that belong to a specific form (that a non-programmer type could easily edit), that the 'generic' form class would read, pull in the element info, and create the form on the fly.
I do realize however this poses another problem which I haven't yet figured out, and that is how to use table lookups for select elements (without coding the database retrieval of the lookup into the form, so that a non-user could easily just define it without any programming, purely configuration, but that is a whole other topic not part of my question here. (and I think I have viable ideas/solutions to that part of the problem anyhow) -- extra config entries and a generic routine pretty much.
I hope that clarifies my thought process and reason why I am doing it the way I am in the example above.
I have not yet played with using a Zend_Config to construct an instance of Zend_Form.
But a look at the code suggests that Zend_Form::addElement() doesn't directly take a Zend_Config instance as a param. Rather, it looks like you need pass your Zend_Config instance to the form constructor. It also seems that the config format needs to be a little deeper in order to map config keys to setXXX() calls.
In path/to/config/myForm.ini:
[myForm]
myForm.elements.site_status.name = "site_status"
myForm.elements.site_status.type = "select"
myForm.elements.site_status.label = "Status"
myForm.elements.site_status.options.multiOptions.active.key = "Active"
myForm.elements.site_status.options.multiOptions.active.value = "Active"
myForm.elements.site_status.options.multiOptions.inactive.key = "Inactive"
myForm.elements.site_status.options.multiOptions.inactive.value = "Inactive"
Then instantiating:
$formConfig = new Zend_Config_Ini('path/to/config/myForm.ini', 'myForm');
$form = new Zend_Form($formConfig);
Not tested, but looking at this example:
Using Zend_Form with Zend_Config - Andrew Vayanis
it feels like it should go something like the above.
Update
In view of the comments/feedback from #Aaron, two more approaches.
We could extend Zend_Form, implementing a method called something like addElementByConfig in which we would pass the shallow Zend_Config instance that describes the element itself. In fact, we could even just override addElement(), taking a recursive approach: if the first param is an instance of Zend_Config, then call addElement() using the component data.
If the atomicity and re-usability are the primary benefits we seek in using Zend_Config to describe an element, then perhaps we just make a custom element extending Zend_Form_Element. Then we could use these elements in any forms we wish.
This is my first post here, so I hope everything is fine.
Here is my problem:
I have a table in my database called UserTypes. It has:
ID;
IsPrivate;
Parent_ID;
The relevant ones are the first and the third one.
I have another table called UserTypes_T which has information for the different types, that is language specific. The fields are:
Language_ID;
UserType_ID;
Name;
What I'm trying to achieve is load the entire hierarchy from the UserTypes table and show it in a TreeView (this is not relevant for now). Then, by selecting some of the user types I can edit them in separate edit box (the name) and a combo box (the parent).
Everything works fine until I try to persist the changes in the database. EF has generated for me two entity classes for those tables:
The class for the user types has:
ID;
IsPrivate;
Parent_ID;
A navigational property for the self-reference (0..1);
A navigational property for the child elements;
Another navigational property for the UserTypes_T table (1..*);
The class for the translated information has:
UserType_ID;
Language_ID;
Name;
A navigational property to the UserTypes table (*..1);
A navigational property to the Languages table (*..1);
I get the data I need using:
return context.UserTypes.Include("UserTypes_T").Where(ut => ut.IsPrivate==false).ToList();
in my WCF Web service. I can add new user types with no problems, but when I try to update the old ones, some strange things happen.
If I update a root element (Parent_ID==null) everything works!
If I update an element where Parent_ID!=null I get the following error:
AcceptChanges cannot continue because the object’s key values conflict with another object in the ObjectStateManager.
I searched all over the internet and read the blog post from Diego B Vega (and many more) but my problem is different. When I change a parent user type, I actually change the Parent_ID property, not the navigational property. I always try to work with the IDs, not the generated navigational properties in order to avoid problems.
I did a little research, tried to see what is the object graph that I get and saw that there were lots of duplicate entities:
The root element had a list of its child elements. Each child element had a back reference to the root or to its parent and so on. You can imagine. As I wasn't using those navigational properties, because I used the IDs to get/set the data I needed, I deleted them from the model. To be specific I deleted points 4 and 5 from the UserTypes entity class. Then I had an object graph with each element only once. I tried a new update but I had the same problem:
The root element was updated fine, but the elements, that had some parents, threw the same exception.
I saw that I had a navigational property in the UserTypes_T entity class, pointing to a user type, so I deleted it too. Then this error disappeared. All the items in the object graph were unique. But the problem remained - I could update my root element with no problems, but when trying to update the children (with no exclusions) I got a null reference exception in the generated Model.Context.Extensions class:
if (!context.ObjectStateManager.TryGetObjectStateEntry(entityInSet.Item2, out entry))
{
context.AddObject(entityInSet.Item1, entityInSet.Item2);//here!
}
I tried to update only the name (which is in UserTypes_T) but the error is the same.
I'm out of ideas and I've been trying to solve this problem for 8 hours now, so I'll appreciate if someone gives me ideas or share their experience.
PS:
The only way I succeeded updating a child object was using the following code to retrieve the data:
var userTypes = argoContext.UserTypes.Include("UserTypes_T").Where(ut => ut.IsPrivate==false).ToList();
foreach (UserType ut in userTypes)
{
ut.UserType1 = null;
ut.UserTypes1 = null;
}
return userTypes;
where UserType1 is the navigational property, pointing to the parent user type and UserTypes1 is the navigational property, holding a list of the child element. The problem here was that EF "fixups" the objects and changes the Parent_ID to null. If I set it back again, EF sets the UserTypes1, too... Maybe there is a way to stop this behavior?
OK everybody, I just found what the problem was and I'm posting the answer if anybody else encounters the same issue.
The problem was that I was making some validation on the server in order to see if there isn't a circular reference between the user types. So, my method on the server looked something like:
using (MyEntities context = new MyEntities())
{
string errMsg = MyValidator.ValidateSomething(context.UserTypes,...);
if (!string.IsNullOrEmpty(errMsg)) throw new FaultException(errMsg);
//some other code here...
context.UserTypes.ApplyChanges(_userType);//_userType is the one that is updated
context.UserTypes.SaveChanges();
}
The problem is that when making the validation, the context is filled and when trying to save the changes, there are objects with the same key values.
The solution is simple - to use different context for validating things on the server:
using (MyEntities validationContext = new MyEntities())
{
//validation goes here...
}
using (MyEntities context = new MyEntities())
{
//saving changes and other processing...
}
Another one can be:
using (MyEntities context = new MyEntities())
{
using (MyEntities validationContext = new MyEntities())
{
//validation
}
//saving changes and other processing...
}
That's it! I hope it can be useful to somebody!
I have a Recommendation object and a FeedbackLevel object and the FeedbackLevel object is a navigation property inside a Recommendation object
Recommendation
int EntityKey;
FeedbackLevel Level;
Inserting a new one works just fine with AddObject(). Here's what I'm trying with the update, which doesn't work.
recommendation.Level = myRepository.GetFeedbackLevel(newLevel);
_context.Recommendations.Attach(new Recommendation { EntityKey = recommendation.EntityKey });
_context.Recommendations.ApplyCurrentValues(recommendation);
_context.SaveChanges(System.Data.Objects.SaveOptions.AcceptAllChangesAfterSave);
The code above is basically a compact version of what I have. Updating a scalar property works just fine, but I can't update a new navigation property as the avove code succeeds without any changes!
I've also tried a few other methods like getting an existing Recommendation first and then re-assigning the FeedbackLevel to it without any luck.
UPDATE:
Here is what I captured from the sql profiler during the save call:
exec sp_executesql N'update [dbo].[Recommendation]
set [FeedbackComment] = #0, [LastUpdatedDate] = #1
where ([RecommendationKey] = #2)
',N'#0 varchar(255),#1 datetime,#2 int',#0='This is cool',#1='2010-01-08 10:06:06.5400000',#2=11
It looks like it does not even know that the FeedbackLevel needs to be saved. How can I get it to trigger it?
Not sure exactly what your trying to do here,
but if your trying to do an update, simple way is to
1) do a, GET [entityName] by id, use include to get any child properties
2) update the attributes
3) make sure the entity state is modified
4) Save changes
By doing a GET first, you wont need to get attach it to the context before you update, as it will be already in there.